I have rough sawn plywood siding. It is like T1-11 in texture. There are two or three coats of paint on it already. I plan on removing only the paint that lost its adhesion. Some of the areas have light hair line cracking, but it is not peeling. I am planning to use Zinsser 123 to help seal and prime the entire house. I am then going to add a coat of SW Superpaint. I just have a couple of questions.
-Should I apply two coats of A100 or Superpaint to the siding?
-Is priming the entire house overkill?
-Will the small check cracking cause problems? The primer seems to seal the cracks. I haven't painted the siding yet, but I think they will be gone with the first coat of paint. You have to be really close to the siding to even see the small cracks.
It's completely unnecessary to prime the entire house. Scrape at the paint with a sharp paint scraper, and if it puts up a respectable fight to stay on, then leave it on. There's no point removing paint that's sticking well only to repaint with paint that won't stick any better.
After you remove any loose paint, sand the edges of the painted areas to "feather-edge" them so that the edges don't show through the new paint.
Then, prime only the bare wood. Paint over the paint.
Two coats will protect the underlying plywood siding twice as well as one coat.
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